Machines, methods and tickets carrying machine readable bar codes to enable point of sale equipment to automatically identify articles sold by supermarkets, department stores and the like are well known. Typically, a ticket, which identifies a specific article of merchandise, is printed at the store and provided with both machine readable bar codes as well as alpha-numeric characters to enable visual article data identification. The printer locates a preselected pattern of vertically oriented bars along a horizontal line with the width of the bars and the spaces between them being varied in accordance with a predetermined code. The bar codes may include inventory identification data, price information, as well as any other desired data.
In many point of sale systems, the reading of a machine bar code is done by the cash register operator who is provided with a manually controlled wand which senses the optical differences presented by the bar code pattern on the ticket. The wand generates an electrical signal representative of the width of the bars and spaces between them. This signal is analyzed by the electronics in the point of sale equipment to produce a variety of functions such as transaction summarizing, inventory control and change calculation, etc. For example, an operator at the counter of a supermarket manually moves the wand to scan the bar code on the ticket attached to the item and thereby automatically enters identification data of the item as well as its price into the point of sale equipment.
One function of the point of sale equipment is to speed up the counter operation. As a result, the operator will quickly manually scan the bar code on the tickets. The tickets may be placed on a wide variety of surfaces (depending upon the item) so that in the process of moving a wand across conventionally low height bar code, care must be exercised to assure that the field of view of the wand remains within the bar code pattern.
As a practical matter, such care tends to slow down the operator whose attention must be continually and accurately focused on the bar codes to avoid straying off the line of the bar code. This high degree of care is, therefore, not consistent with the desired higher operating speed of a cash register operator.
One method for facilitating scanning of the bar code pattern involves an increase in the vertical height of a bar code by increasing the height of each line of printing bar codes. This method involves an expensive and elaborate modification of the printing equipment since the drums employed in printing bar codes normally accommodate a maximum bar height of about 3/32 of an inch. Such modification of the printer would increase its cost to the store where it is used.